1. Technical Field
The present invention relates to a pump and, more particularly, to a reciprocating electromagnetic type pump.
2. Background Art
Typically, electrically driven reciprocating pumps include an electric motor, a motion translation means, and a pumping element of some kind. To make the motor work, a magnetic field is generated by the motor coils and this magnetic field creates tangential forces to turn the motor's rotor.
There have been many attempts in the past to eliminate the electric motor by applying magnetic forces to drive a pump plunger directly. Examples of these designs are shown in Hirabayashi et al. U.S. Pat. No. 5,472,323 issued Dec. 5, 1995 and Olson U.S. Pat. No. 7,288,085 issued Oct. 30, 2007. By employing such designs, many mechanical components can be eliminated from the pump system, including bearings, sliding seals, and rotors.
While having direct plunger drive capability, these past pump designs did not take full advantage of the direct magnetic drive. They were still complex mechanisms, they still required check valves to prevent backflow, and they were difficult to disassemble if they required cleaning or maintenance. Check valves are an especially troublesome component, since they have a tendency to leak or sometimes stick after a long idle period. In addition, check valves are usually not reversible, allowing fluid to flow in only one direction. In addition, the material from which check valves are constructed, namely, springs, balls, and the like, are incompatible with many fluids that are being moved through the pump.
While many of the prior art devices may be sufficient for their intended function, other constructions may provide features that may be more desirable to a user. It might be more advantageous to provide a pump that does not employ check valves or wearable seals, that is reversible, that is simple and easy to disassemble, that is made with materials compatible with the fluids being pumped, and that is scalable for use in small and large volume applications.